Massachusetts Sen. Elizabeth Warren raised $19.1 million for her 2020 presidential bid in the second quarter of the year, according to her campaign. The haul is more than triple the amount she raised in the first quarter and leaves her with nearly $20 million on hand.

Warren’s second quarter total trails only South Bend, Indiana, Mayor Pete Buttigieg’s $24.8 million and former Vice President Joe Biden’s $21.5 million among candidates who have released their fundraising numbers so far. Detailed reports for the quarter are due to the Federal Election Commission by July 15.

The impressive amount is something of a validation for Warren’s strategy of relying on grassroots online donations and not holding in-person, high-dollar fundraisers. Democratic strategists and other campaigns had questioned whether or not Warren could pay for her extensive campaign operation without setting aside time to collect maximum-donation checks. So far, she has more than 300 staffers, most of whom are working in the four early primary states.

“You’re making it possible to build a presidential campaign without catering to wealthy donors—with no closed-door fundraisers, no Super PACs, and no money from Washington lobbyists, corporate PACs, or, for that matter, PACs of any kind,” Roger Lau, Warren’s campaign manager, wrote in an email to supporters that will go out this afternoon.

Among other top-tier candidates, California Sen. Kamala Harris raised $12 million and Vermont Sen. Bernie Sanders — who also eschews high-dollar fundraising — collected $18.2 million in the second quarter.

Lau seemed to allude to Warren raising more than Sanders in his e-mail. “We raised more money than any other 100% grassroots-funded campaign,” he wrote. “That’s big.”

Warren’s campaign said it now has $19.7 million on hand. That trails Sanders, who has $28 million in the bank, and Buttigieg, who has $22.6 million on hand. Harris and Biden did not release cash-on-hand totals.

The average donation to Warren’s campaign was $28, and more than 384,000 people have donated so far, according to Lau’s e-mail to supporters.

The overwhelming majority of the cash Warren has raised is for the Democratic primary race, her campaign said, with only about $100,000 set aside for the general election.

After launching her campaign in February, Warren raised just $6 million in the first quarter of the year, prompting questions about whether or not she’d be able to raise adequate funds to stay in the race.